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How to extract one column of a csv file
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The simplest way I was able to get this done was to just use csvtool. I had other use cases as well to use csvtool and it can handle the quotes or delimiters appropriately if they appear within the column data itself.
csvtool format '%(2)\n' input.csv
Replacing 2...
When should I use semicolons in SQL Server?
...t have been introduced in recent years. (MERGE too for example). As mentioned in other answers, in the ANSI standard they are required
– Mark Sowul
Jul 28 '17 at 18:16
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Running a cron every 30 seconds
... not go down to sub-minute resolutions, you will need to find another way.
One possibility, though it's a bit of a kludge(a), is to have two jobs, one offset by 30 seconds:
# Need these to run on 30-sec boundaries, keep commands in sync.
* * * * * /path/to/executable param1 param2
* * *...
When to use static vs instantiated classes
... a life on its own)
(Yeah, I admit, really really overly-simplified...)
One thing about static methods/classes is that they don't facilitate unit testing (at least in PHP, but probably in other languages too).
Another thing about static data is that only one instance of it exists in your program...
Computed / calculated / virtual / derived columns in PostgreSQL
...STORED
);
db<>fiddle here
VIRTUAL generated columns may come with one of the next iterations. (Not in Postgres 13, yet) .
Related:
Attribute notation for function call gives error
Until then, you can emulate VIRTUAL generated columns with a function using attribute notation (tbl.co...
How is the fork/join framework better than a thread pool?
... stealing would be like this: Worker B has finished his work. He is a kind one, so he looks around and sees Worker A still working very hard. He strolls over and asks: "Hey lad, I could give you a hand." A replies. "Cool, I have this task of 1000 units. So far I have finished 345 leaving 655. Could ...
How are ssl certificates verified?
...he certificate authority that the address listed in the certificate is the one to which it has an open connection.
Your web browser generates a shared symmetric key which will be used to encrypt the HTTP traffic on this connection; this is much more efficient than using public/private key encryption...
Importing two classes with same name. How to handle?
...og4j.Logger and java.util.logging.Logger. Usually, I have no control over one side or the other; I'm doing legacy code integration.
– kevinarpe
Jul 1 '15 at 11:07
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What are the pros and cons of performing calculations in sql vs. in your application
...t the db server will save bandwidth, and disk io if the aggregates can be done inside indexes)
convenience (sql is not the best language for complex work - especially not great for procedural work, but very good for set-based work; lousy error-handling, though)
As always, if you do bring the data ...
Find running median from a stream of integers
...solution works is explained below:
For the first two elements add smaller one to the maxHeap on the left, and bigger one to the minHeap on the right. Then process stream data one by one,
Step 1: Add next item to one of the heaps
if next item is smaller than maxHeap root add it to maxHeap,
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